English abbreviation of Fund, translated into Chinese as "transactional open index fund", also known as exchange traded fund. ETF is essentially an open-end fund, which is not essentially different from the existing open-end funds. But it also has its own distinct personality in three aspects: first, it can be listed and traded on the exchange, and investors can buy and sell ETF shares directly on the exchange like trading individual stocks and closed-end funds; Second, ETF is basically an index-type open-end fund, but compared with the existing index-type open-end fund, its biggest advantage is that it is listed on the exchange and the transaction is very convenient; Third, its purchase and redemption also has its own characteristics. Investors can only subscribe or redeem ETFs with a basket of stocks corresponding to the index, but not with existing open-end funds for cash subscription and redemption.

As an open-end fund, the scale after issuance is not fixed, and investors can purchase and redeem it.